Inkjet printers are now very common and affordable and allow one to obtain decent print quality. They are used in home printing, office printing and commercial printing. The growth of inkjet printing is a result of a number of factors including reductions in cost of inkjet printers and improvements in print resolution and overall print quality. A continued demand in inkjet printing has resulted in a need to produce images of high quality, high permanence and high durability while maintaining a reasonable cost.
Inkjet printing is a popular method of non-contact printing on a broad selection of substrates. One popular variety of inkjet printing involves using UV curable inkjet inks, which enable high printing speed. UV curable inkjet inks have relatively good adhesion on variety of substrates and they have low Volatile Organic Compound (VOC) content. There are two types of UV inks, radical curing inks and cationic curing inks or hybrids thereof. The majority of inks currently used in the industry are radical inks although some cationic inks exist.
One of the major shortcomings of UV curable components is that a majority of such components have intrinsic high viscosity, which limits the ink design space and the ability to formulate inks suitable for inkjet application. This problem is common for both radical UV curable components and cationic UV curable components. Mill bases are employed in the milling of pigment particles to further the dispersion of the particles in a resulting ink. The mill bases used in the preparation of UV curable inkjet inks are characterized by relatively high pigment load, which is at least 20% by weight pigment content in the mill base.